On 24/08/04, Michel Merten wrote:
> I used to work for years in the chemical business (polymers) and I
> remember of many high tech and demanding applications (injection
> moulding of medical parts, fine fibers, ...) for which even minor
> changes in the polymerisation reactor conditions on a specific
> supplier product line would impact the final quality of the finished
> good and make it improprer for use. (change of melt flow, or other
> physical parameters). So only a very few selected polymer suppliers
> were approved for specific applications and specific grade quality had
> to be always delivered according to most stringent controls (lot per
> lot analysis, treacibility, ...). When adding pigments this makes it
> even more difficult as getting proper mixing within the polymer adds
> to the complexity.
Good point. A dye would have less effect than a pigment on the physical
properties of the polymer.
> Does anyone has information on that aspect of the CD production
> process : polycarbonate grade selection, approval, lot traceability at
> CD plants; it could also have implications in the "lot per lot"
> problems we sometimes notice on the CD we buy.
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